• The Pure and Applied Mathematics
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• v.19 no.4
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• pp.349-361
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• 2012

CAT(0) cubical complexes are a key to formulate geodesic spaces with nonpositive curvatures. The paper discusses the median structure of CAT90) cubical complexes. Especially, the underlying graph of a CAT(0) cubical complex is a median graph. Using the idea of median structure, this paper shows that groups acting on median complexes L(${\delta}$) groups and, in addition, work L(0) groups are closed under free product.

• Kyungpook Mathematical Journal
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• v.60 no.2
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• pp.387-399
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• 2020

In this paper, we study a problem of a non-constant entire function f that shares a set S = {a, b, c} with its k-th derivative f^(k), where a, b and c are any three distinct complex numbers. We have found a gap in the statement of the main result of Chang-Fang-Zalcman [10], and with the help of their method, we have generalize their result in a more compact form. As an application, we generalize the famous Brück conjecture [9] with the idea of set sharing.

• Kyungpook Mathematical Journal
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• v.50 no.4
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• pp.557-564
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• 2010

By using an idea of C$\u{a}$dariu and Radu [4], we prove the generalized Hyers-Ulam stability of the functional equation f(x + y,z - w) + f(x - y,z + w) = 2f(x, z) + 2f(y, w). The quadratic form $f\;:\;\mathbb{R}\;{\times}\;\mathbb{R}{\rightarrow}\mathbb{R}$ given by f(x, y) = $ax^2\;+\;by^2$ is a solution of the above functional equation.

• Journal of applied mathematics & informatics
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• v.1 no.1
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• pp.55-74
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• 1994

We consider an M/G/1 queueing system with multiple priority classes of jobs. Considered preemptive rules are the preemptive-resume preemptive-repeat-identical, and preemptive-repeat-different policies. These three preemptive rules will be analyzed in parallel. The key idea of analysis is based on the consideration of a busy period as composite of delay cycle. As results we present the exact Laplace-Stieltjecs(L.S) transforms of residence time and completion time in the system.

• Education of Primary School Mathematics
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• v.4 no.2
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• pp.105-110
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• 2000

This paper is discussing about the culture of mathematics classroom for problem solving. The mathematics classroom which we have to aim at is where every students make proper belief and attitude about mathematics, and also can express their own idea and make question freely. In that classroom, the students can meet with various problem solving methods and communicate with other students, and then elaborate their own method.

• Korean Journal of Mathematics
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• v.5 no.1
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• pp.9-16
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• 1997

In this paper, we construct new classes from the idea of [6, Theorem 2.1] and show that the property of operators belonging to the classes is inherited by certain dilations. And we also prove that the existence of common noncyclic vectors for certain families is equivalent to the existence of infinite dimensional common semi-invariant subspace of operators.

• Kyungpook Mathematical Journal
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• v.20 no.1
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• pp.37-45
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• 1980

The Riemannian space of recurrent curvature was defined and studied by Ruse [8] and Walker [10]. In 1963, $M{\acute{o}}or$ [4] generalised this idea for Finsler spaces and defined and studied Finsler spaces of recurrent curvature. These spaces for various curvature tensors have subsequently been studied by Mishra and Pande [1], Sen [9] and Misra [3] etc. The purpose of the present paper is to study Finsler space based on the recurrency of the curvature tensors derived from non-linear connections.

• Education of Primary School Mathematics
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• v.3 no.2
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• pp.143-149
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• 1999

The Assessment using the observation is one of the common ways to know what the student knows and dose not. Using the obserbational Assessment, Teachers, analyzing student's growth, provide appropriate feed-back, and so they try to record every activities. but, accumulatively recording the result of observational assessment face time·spacial limits. and it is difficult to apply in a real classroom situation. Taking these into consideration, I'd like to take a look at the idea of check-list assessment that could record data observing student and contrive a practical ways of application.

• Education of Primary School Mathematics
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• v.3 no.2
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• pp.115-131
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• 1999

The purpose of this study is to examine meaning, factors, and diagnostic method of underachievers in mathematics and to propose the idea of the individualized teaching method for underachievers. For the first purpose, previous literatures on underachievers are reviewed. For the second purpose, this study described the procedure of developing the individualized instructional program, and the method of diagnosing and prescribing errors in mathematics. In the future, individualized instructional program need to be developed based on correct diagnosis of factors effecting under achievement for the effective teaching of underachievers.

• The Pure and Applied Mathematics
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• v.17 no.4
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• pp.307-319
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• 2010

We provide a new semilocal convergence analysis of the Gauss-Newton method (GNM) for solving nonlinear equation in the Euclidean space. Using our new idea of recurrent functions, and a combination of center-Lipschitz, Lipschitz conditions, we provide under the same or weaker hypotheses than before [7]-[13], a tighter convergence analysis. The results can be extented in case outer or generalized inverses are used. Numerical examples are also provided to show that our results apply, where others fail [7]-[13].